A person can build a decent truing stand for a very few bucks. I saw one of these in a person's garage and it looked like it worked well. Grab a used front fork from a junker. Split the head tube into three or four pieces. Bend them outward. Flatten the ends, drill a hole in each of the strips, and screw them drown into a block of wood. Clamp the wood on a worktable. Drill a few holes through the arms. Insert some bent up all thread (1/4-20 works well) through the holes. Bend them sharply in a "crank" shape. Secure them with a hex nut on the inside and a wing nut on the outside. Mark the hex nut with a file to keep track of turns. Adjust the all thread arms as required to clear the rim. Rotate the "cranks" for OD measurements. Loosen the wing nuts and adjust the hex nuts for lateral runout.